Look at the point table first!
There are 5 teams playing in the competition for the Charity. Hence, there are 10 possible matches between the teams like below.
DareDevils vs SuperKings
DareDevils vs Royals
DareDevils vs Sunrisers
DareDevils vs Riders
SuperKings vs Royals
SuperKings vs Sunrisers
SuperKings vs Riders
Royals vs Sunrisers
Royals vs Riders
Sunrisers vs Riders
For winning team, 2 points must have been given & for playing a draw 1 point must have been given to each team.
So there are 10 matches & total points distributed must be 10 x 2 = 20.
Adding up points of all teams 6 + 5 + 4 + 2 + Riders = 20. That gives Riders = 3.
Hence point score of Riders is 3!